Wireless receiving apparatus



UNITED STATES PATENT OFFICE.

ERNsT a. BERG, F scHENEoTAnY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC com- PANY, A cORPORATION OF NEW YORK.

wIREL ss RECEIVING APPARATUS.

To all whom it may concern:

Be it known that I, ERNST J. BERG, a citizen of the United States, residing at Schenectady, county of Schenectady, in the State of New York, have invented certain new and useful Improvements in Wireless Receiving Apparatus, of which the following is a specification.

My present invention relates to wireless signaling systems and more particularly to '20 provide a receiving apparatus which will be capable of receiving signals from a certain desired direction to the exclusion of signals and strays coming from other directions.

The novel features which I believe to be characteristic of my invention are set forthwith particularity in the appended claims. The invention itself, however, both as to its organization and mode of operation will .best be understood by reference to the fol- 'lowing description when taken ,in connection with the accompanying drawing in which I have indicated, partly in diagram, one embodiment of my invention Y As indicated in the drawing my receiving apparatus comprises a coil 1 made up of a large number of turns of insulated wire. Within this coil and at right angles to the plane of the coil I place a number of sheets of copper 2, or other metal having good conduc- 4 tivity. These metal sheets are supported in a framework 3 which is mounted upon the rotatable standard 5having a handle 6 upon its end whereby the entire structure may be rotated in a horizontal plane. I have shown the coil 1 as being supported directly by the I copper sheets 2 but the turns of this coil.

may be mounted upon a separate form if desired, the only essential feature of the construction being that it shall be positioned at a right angle to the copper sheets. The terminals 7 and 8 of the coil 1 are connected to the grid 9 and cathode 10 of a receiving device 11 of the audion type and the signals to be received will cause a response in the Specification of Letters Patent.

Patented Sept. 7, 1920.

Application filed February 13, 1917. Serial No. 148,400.

telephone receiver 12 which is included in a circuit which comprises the cathode 10, an? ode 13 and a local battery 14. The telephone receivers are preferably shunted by a condenser 15 which serves as a by-path for the radio frequency component of the current flowing in the circuit. A variable condenser 16 serves to tunethe receiving circuit to the frequency of the waves to be received and a condenser 17 in series with the grid 9 5 may be employed to assist the device 11 in its action as a detector.

The operation of my receiving apparatus is as fol-lows: If the signal which is to be received comes from a direction in the plane of the coil 1 there will at any given instant be a certain phase difference between the A waves cutting the two sides of the eoil.- Because of this a resultant electromotive force will be set up in the coil, which electromotive force will be applied tothe grid of the receiving device and will produce an indication in the telephone receiver. If a wave comes from a direction at right angles to the plane of the coil the waves cutting the two sides of the coil will always be in phase and no resultant electromotive force will be set up in the coil. It will be apparent that if the coil is rotated from a position where it is at right angles to the direction of the received waves toward a position where it is parallel to their direction that an electromotive force will be produced in the coil which increases in magnitude as the-phase difference betweenthe waves cutting the two sides of the coils increases until the point is reached where this phase difference is greatest and that this condition will occur when the coil is parallel to the direction of the received waves. Hence by rotating the coil until the point is reached where the received signals are strongest it will be possible to determine with a considerable degree of accuracy the direction fromwhich the re ceived signals come.

The metal sheets 2 are in effect short circuited coils of low impedance, and-in fact if desired may be replaced by actual coils of low impedance. Electromagnetic waves coming from the desired direction will pass through these sheets without producing any currents therein, since they are at right angles to the direction of the waves and hence without any loss. of energy. Signals or strays coming from other directions, how-, 110

, -esipated in the sheets and their effect in the coil 1 will be so small that it will not inter- .fere with the reception of the desired waves.

What I claim as new and desire to secure by Letters Patent of the United States is: 1. The method of directive receiving of wireless signals by means of a receiving coil which consists in utilizing said coil as a receiving antenna, rotating the coil in a horizontal plane until the response in receiving apparatus connected thereto is a maximum for the desired signals and at the same time absorbing the energy of undesirable impulses of all frequencies in such a way that they will produce substantially no effect 1n the receiving coil.

2. The method of directive receiving of wireless signals by means of a receiving coil which consists in utilizing said coil as a receiving antenna, rotating the coil in a horizontal plane until the response in receiving apparatus connected thereto is, a maximum for signals coming from a desired direction and at the same time absorbing the energy of signal impulses of all frequencies coming from other directions in such a way that they will produce substantially no effect in the receiving coil.

3. The method of directive receiving of wireless signals by means of a receiving coil which consists in utilizing said coil as a receiving antenna, rotating the coilin a horizontal plane until the response in receiving apparatus connected thereto is a maximum for signals coming from a desired direction and at the same time absorbing the energy of signal impulses of all frequencies coming from other directions in low lmpedance circuits which are so located that they are substantially unaffected by the desired signals. I

i In witness whereof I have hereunto set my hand this. 12th .day of February, 1917.

ERNST J. BERG. 

